11,12-epoxyerythromycins

ABSTRACT

COVERS 11, 12-EPOXYERYTHROMYCINS WHICH ARE USEFUL AS ANTIBIOTICS.

3,816,397 11,12-EPOXYERYTHROMYCINS John Soloman Tadanie'r, Chicago, and Jerry Roy Martin, Waukegan, 11]., assignors to Abbott Laboratories,

Chicago, Ill. No Drawing. Filed June 15, 1972, Ser. No. 263,056 Int. Cl. C07c 129/18 US. Cl. 260-210 E 3 Claims ABSTRACT OF THE DISCLOSURE Covers 11,12-epoxyerythromycins which are useful as antibiotics.

DESCRIPTION OF INVENTION This invention relates to 11,12-epoxyerythromycins which possess antibiotic activity.

Erythromycin is produced in two forms denoted A and B by cultivating a strain of Streptamyces erythreus in a suitable nutrient medium as is taught in U.S. 2,653,899, Bunch et al. The structure of erythromycin is represened by the following formula:

(desosamine) cu,

(cladinose) (erythronolide) In this formula, when R R and R represent hydrogen and R represents hydroxyl, the structure illustrated is erythromycin A. When R is, however, also hydrogen, the structure of erythromycin B is illustrated. The term erythromycin when used herein without modification is meant to embrace both forms, that is, erythromycin A and erythromycin B.

Erythromycin, as will be noted from the formula, comprises three cyclic fragments. These fragments are referred to respectively as cladinose, desosamine and erythronolide, The positions on the cladinose ring are indicated by double primed numbers; the positions on the desosamine ring by single primed numbers; while positions on the erythronolide ring are indicated by unprimed numbers.

The first step in producing the compounds here is to provide a 11-0-methanesulfonylerythromycin A or enol ether thereof. This is prepared according to the techniques outlined in co-pending, commonly assigned application, filed as of even date, bearing Ser. No. 263,087. To prepare l1, 12-epoxyerythromycin A 11-O-methaneulfonyl A derivative is treated with l,5-diazabicyclo[5.4.0]undecene-S in an inert solvent such as xylene, methylene chloride, or another inert hydrocarbon, toluene, or benzene at low temperature, say -5" C. to prepare the enol ether of the above the reaction is carried out at reflux temperature for 12-24 hours.

Another way of obtaining the 11,12-epoxyerythrornycin is to treat the erythromycin A enol ether with aqueous acetic acid. Normally the amount of acid in proportion to water is 30-60% acid based on the total volume of Water and acid. In a typical case a 1:1 volume of glacial acetic to water is used.

The following examples illustrate preparation of the compounds of the invention.

United States Patent Office Patented June 11., 1 97 1 EXAMPLE 1 11,12-epoxyerythromycin A enol ether A solution prepared from 2.2 g. of II-O-methanesulfonylerythromycin A enol ether, 3.0 g. of 1,5-diazabicyclo [5.4.0]undecene-5, and 36 ml. of benzene was heated under reflux for 18 hours. The product (1.74 g. of a white glass) was isolated by benzene extraction. Partition column chromatography of 1.1 g. gave 834 mg. of pure 11, 12-epoxyerythromycin A enol ether as a white glass [011 42; IR: 3590 (shoulder), 3550, 3500-3400, 1727 cm.- ;NMR: 6 3.28 (OCH 2.28 (N'Me 1.62 (CgCHg), 1.39 (C -CH Anal. Calcd. for C3'7H63011N: C, 63.68; 'H, 9.10; N, 2.01. Found: C, 63.81; -H, 9.14; N, 1.90.

EXAMPLE 2 11,12-epoxyerythromycin A A solution prepared from 15.8 g. of II-O-methanesulfonyl- '-Oacetyl-4"-O formylerythromycin A, prepared as described in Example 1, 6.8 g. of 1,5-diazabicyclo [5.4.0]undecene-5 and ml. of benzene was stirred at 50 C. for 18 hours. Benzene (98 ml.) and water (98 ml.) were added and the resulting mixture was stirred at room temperature for 1 hour.

The resulting mixture was shaken with a mixture of 500 ml. of benzene and 800 ml. of 5% NaHCO The aqueous phase was separated and extracted with 700 ml. of benzene. The benzene solutions were washed in series with three 600-ml. portions of water, combined, and dried over anhydrous magnesium sulfate. Evaporation of the benzene under reduced pressure left 12.9 g. of 2-O-acetyl- 4"-O-formyl-11,12-epoxyerythromycin A.

A solution prepared from 4.0 g. of 2'-O-acetyl-4"-O- formyl-l1,12-epoxyerythromycin A, prepared as described above, 9 ml. of 5% aqueous NaHCO and 88 ml. of methanol was stirred at room temperature for 48 hours. The resulting solution was shaken with a mixture of 600 ml. of chloroform and 600 ml. of 5% NaHCO The chloroform solution was washed with three 600 ml. portions of water. Evaporation of the chloroform under reduced pressure left 3.58 g. of an orange oil. Partition column chromatography of 3.5 g. of this material yielded 1.5 g. of pure 11,12-epoxyerythromycin A, and as amorphous white glass composed of a 1.2 to 1 mixture of tautomeric forms: 11,12-epoxyerythromycin A (a) and 11,12-epoxyerythromycin A 6,9-hemiacetal (2). Crystallization from ether gave the pure crystalline 11,12-epoxy erythromycin A 6,9-hemiacetal (2), MP. 158-162",

[:];5 90, IR: 3578, 3500-3400, 1727 cm." NMR: (J'11=10-0 HZ-, C -H), (NMe 1.66 (C -CH Anal. Calcd. for C H NO C, 62.08; H, 9.15; N,

agar dilution units, in order to determine the MIC value in micrograms/ml. one must divide the con centrations of 4 by the number of agar dilution units, here 10, and multiply by 1000.

The compound here was tested as to its activity against 1.96. Found: C, 62.14; H, 9.34; N, 1.77. 5 the following organisms:

I EXAMPLE 3 ECR =Multiple drug resistant Escherichia coli SF=Strept0c0ccus faecalzs ATCC 10541 N CH PA=Pseudomonas aeruginosa BMH #1 3 2 10 SA=Staphyloc0ccus aureus ATCC 6438P EC=Escherichia c011 ATCC 26 BS=Bacillus subtilis #10707 (University of Ill.) PV=Pr0teus vulgaris ATCC 6897 CH, SS=Shigella sonnei ATCC 9290 ST =Salm0nella typhosa ATCC 9992 H KP=Klebsiella pneumoniae ATCC 10031. 43H 50H, Results are as follows:

TABLE I Ecru SF PA. SA. EC BS PV ss ST 'KP Example I, 1 mgJml 0 320 0 40 0 160 0 40 10 160 160 160 160 160 160 so 11,12-epoxyerythromycin A What is claimed is: 1. An er throm cin derivative selected from the ou A solutlon prepared from 612 of lllz'epoxyerytb consisting if 11 lg-epoxyerythromycin A 6 9 enol the i' romycin A enol ether prepared by the method of Examand 11 lz epoxygrythromycin A ple 1, 9.6 ml. of glacial acetic acid and 9.6 m1. of water 2 The derivative of Claim 1 which is lllz epoxyeryth was allowed to stand at room temperature for 0.5 hours. romycin A 6 9 enol ether The resulting solution was then added dropwise, over a period of 10 minutes to a stirred suspension of 30 g. of g g g of damn I Yvhlch 1S lllzi'epoxyeryth' solid NaHCO in 300 ml. of water. The aqueous solution References Cited was extracted with 200 ml. of chloroform, and the chloroform solution was washed with two ISO-ml. portions of UNITED STATES PATENTS 7 water. Evaporation of the chloroform left 641 mg. of 3,674,773 7/1972 Kurath E white 'glass. Partition column chromatography gave 297 3,681,323 8/1972 Kurath et a1 E mg. of pure 11,12-epoxyerythromycin A, identical with 1 that prepared by the method of Example 1. OTHER REFERENCES- A representative compound was then tested for its activity against gram positive and gram negative bacteria 40 Chem Abst' 1971 1434s in an agar dilution test. Results are given in agar dilution units. These may be converted to MIC values (minimum JOHNNIE W 'f Exammer inhibitory concentrations) expressed in micrograms/ml. OWENS, Asslstant Examiner by merely dividing the agar dilution units into the concentration and multiplying by the proper factor. Thus, 5 US for example, if one tested a sample at a concentration of 4 mg./ml., and determined it had an activity of 10 

